A novel fault observer design method is proposed for a class of nonlinear discrete systems with disturbances,sensor faults,and actuator faults.This method considers both the type of faults and the convergence rate of fault estimation errors,making the fault estimation method more applicable.Firstly,an augmented vector containing system states and sensor faults is constructed to obtain an equivalent generalized system.Secondly, considering the actuator faults in the system and the speed of fault estimation,a fault observer is constructed that includes system state,actuator faults,and sensor faults,and the sufficient conditions for the existence of the fault observer are given.Finally,a nonlinear discrete system model such as the longitudinal movement system of an aircraft is used to estimate the augmented state vector robustly,and the fault estimation results verify the superiority of the proposed method.